On Plant Pathoixxiy and Ha(.ti:kk)i.ogv 123 



many swimming about. At 10:20 [o'clock he] found a conidium 

 the protoplasm of which appeared to be segmenting." He ob- 

 served this conidium until 10:'S0 o'clock, made six drawings "of 

 the changes which occurred during this period. In five minutes 

 after 1 began to watch," he wrote in a memorandum, " all at once 

 one end of the conidium gave way and the swarm spores came out 

 rapidly one after another or two or three together. There were 

 11 in this conidium," and he drew 



the appearance of the c-ell two minutes after the rupture. Four of the 

 swarm spores remained inside the conidium, and apparently could not get 

 out. The cell walls appeared to be elastic and by contraction of the rup- 

 ture so narrow the opening as to make escape impossible. The spores 

 moved about actively inside the cell for some time but did no[t} so crowd 

 or get into each other's way as to block the passage out. Several times a 

 spore was alone and actively moving at the ruptured end, but apparently 

 could not get out. The movement of the spores inside ceased in about 

 25-30 min[utes} after the rupture of the conidium. Those which escaped 

 soon became active and swam away. I could not see any movements of 

 cilia inside the cell before its rupture, as I was easily able to in a prior 

 observation. 



On October 16 another adventure in research took place. His 

 memorandum read: 



\Xhile examining Perotiospora found on my slide several fine patches 

 of 2o5gleas form of Bacteriuvi termo. At first all appeared to be motion- 

 less but in course of an hour several patches began to break up the indi- 

 viduals becoming very active. I several times fixed my attention on 

 motionless individual cells of the zoogleas mass and saw them become 

 detached after a time and begin actively swimming about. By the end of 

 an hour the field was full of actively moving figure-eights — thousands of 

 them, and some of the zooglea:; masses were half broken up. 



On October 30 he sowed in a watch-glass of water " conidia of 

 Cystopus candidtis from Capsella Biirsa-Pastoris." This was 

 another species of fungus of the order Peronosporaceae and the 

 cause of the "white rust disease of cabbages." ^^'^ Again he took 

 data on time, temperature, the appearance of swarm spores, and 

 the break-up of conidia. This time he observed the protoplasm 

 break down 



into an amorphous or slightly granular mass. . . . Another swarm spore 



F. L. Scribner, op. cit., 85. 



